很多人都有做数据采集的需求，用不同的语言，不同的方式都能实现，我以前也用C#写过，主要还是发送各类请求和正则解析数据比较繁琐些，总体来说没啥不好的，就是效率要差一些，
用nodejs写采集程序还是比较有效率（可能也只是相对C#来说），今天主要用一个示例来说一下使用nodejs实现数据采集器，主要使用到request和cheerio。
request :用于http请求
https://github.com/request/request
cheerio:用于提取request返回的html中需要的信息（和jquery用法一致）
https://github.com/cheeriojs/cheerio
单独去说API用法没什么意思也没必要记住全部API，下面开始示例
还是说点闲话：
nodejs开发工具还是很多，以前我也很推荐sublime，自从微软推出了Visual Studio Code后就转用它去做nodejs开发。
用它开发还是比较舒服的，免配置、启动快、自动补全、查看定义和引用、搜索快等，有VS的一贯风格，应该会越做越好，所以推荐一下^_^!
示例要求
从 http://36kr.com/ 中抓取其中文章的“标题”、“地址”、“发布时间”、“封面图片”
采集器
1.建立项目文件夹sampleDAU
2.建立package.json文件
{ "name": "Wilson_SampleDAU", "version": "0.0.1", "PRivate": false, "dependencies": { "request":"*", "cheerio":"*" }}3.在终端中用npm安装引用
cd 项目根目录npm install
4.建立app.js编写采集器代码
首先要用浏览器打开要采集的URL,使用开发者工具查看HTML结构，然后根据结构写解析代码
/** 功能: 数据采集* 创建人: Wilson* 时间: 2015-07-29*/var request = require('request'), cheerio = require('cheerio'), URL_36KR = 'http://36kr.com/'; //36氪 /* 开启数据采集器 */ function dataCollectorStartup() { dataRequest(URL_36KR); }/* 数据请求 */function dataRequest(dataUrl){ request({ url: dataUrl, method: 'GET' }, function(err, res, body) { if (err) { console.log(dataUrl) console.error('[ERROR]Collection' + err); return; } switch(dataUrl) { case URL_36KR: dataParse36Kr(body); break; } }); }/* 36kr 数据解析 */function dataParse36Kr(body){ console.log('============================================================================================'); console.log('======================================36kr=================================================='); console.log('============================================================================================'); var $ = cheerio.load(body); var articles = $('article') for (var i = 0; i < articles.length; i++) { var article = articles[i]; var descDoms = $(article).find('.desc'); if(descDoms.length == 0) { continue; } var coverDom = $(article).children().first(); var titleDom = $(descDoms).find('.info_flow_news_title'); var timeDom = $(descDoms).find('.timeago'); var titleVal = titleDom.text(); var urlVal = titleDom.attr('href'); var timeVal = timeDom.attr('title'); var coverUrl = coverDom.attr('data-lazyload'); //处理时间 var timeDateSecs = new Date(timeVal).getTime() / 1000; if(urlVal != undefined) { console.info('--------------------------------'); console.info('标题：' + titleVal); console.info('地址：' + urlVal); console.info('时间：' + timeDateSecs); console.info('封面：' + coverUrl); console.info('--------------------------------'); } };}dataCollectorStartup();测试结果
这个采集器就完成了，其实就是request一个get请求，请求回调中会返回body即HTML代码，通过cheerio库以jquery库语法一样操作解析，取出想要的数据！
做一个采集器DEMO上面就基本完成了。如果需要长期使用为了防止网站屏蔽，还是需要加入一个代理列表
为示例我从网上的免费代理中提出一些做示例，制作成proxylist.js，其中提供一个随机取一条代理的函数
var PROXY_LIST = [{"ip":"111.1.55.136","port":"55336"},{"ip":"111.1.54.91","port":"55336"},{"ip":"111.1.56.19","port":"55336"} ,{"ip":"112.114.63.16","port":"55336"},{"ip":"106.58.63.83","port":"55336"},{"ip":"119.188.133.54","port":"55336"} ,{"ip":"106.58.63.84","port":"55336"},{"ip":"183.95.132.171","port":"55336"},{"ip":"11.12.14.9","port":"55336"} ,{"ip":"60.164.223.16","port":"55336"},{"ip":"117.185.13.87","port":"8080"},{"ip":"112.114.63.20","port":"55336"} ,{"ip":"188.134.19.102","port":"3129"},{"ip":"106.58.63.80","port":"55336"},{"ip":"60.164.223.20","port":"55336"} ,{"ip":"106.58.63.78","port":"55336"},{"ip":"112.114.63.23","port":"55336"},{"ip":"112.114.63.30","port":"55336"} ,{"ip":"60.164.223.14","port":"55336"},{"ip":"190.202.82.234","port":"3128"},{"ip":"60.164.223.15","port":"55336"} ,{"ip":"60.164.223.5","port":"55336"},{"ip":"221.204.9.28","port":"55336"},{"ip":"60.164.223.2","port":"55336"} ,{"ip":"139.214.113.84","port":"55336"} ,{"ip":"112.25.49.14","port":"55336"},{"ip":"221.204.9.19","port":"55336"} ,{"ip":"221.204.9.39","port":"55336"},{"ip":"113.207.57.18","port":"55336"} ,{"ip":"112.25.62.15","port":"55336"} ,{"ip":"60.5.255.143","port":"55336"},{"ip":"221.204.9.18","port":"55336"},{"ip":"60.5.255.145","port":"55336"} ,{"ip":"221.204.9.16","port":"55336"},{"ip":"183.232.82.132","port":"55336"},{"ip":"113.207.62.78","port":"55336"} ,{"ip":"60.5.255.144","port":"55336"} ,{"ip":"60.5.255.141","port":"55336"},{"ip":"221.204.9.23","port":"55336"} ,{"ip":"157.122.96.50","port":"55336"},{"ip":"218.61.39.41","port":"55336"} ,{"ip":"221.204.9.26","port":"55336"} ,{"ip":"112.112.43.213","port":"55336"},{"ip":"60.5.255.138","port":"55336"},{"ip":"60.5.255.133","port":"55336"} ,{"ip":"221.204.9.25","port":"55336"},{"ip":"111.161.35.56","port":"55336"},{"ip":"111.161.35.49","port":"55336"} ,{"ip":"183.129.134.226","port":"8080"} ,{"ip":"58.220.10.86","port":"80"},{"ip":"183.87.117.44","port":"80"} ,{"ip":"211.23.19.130","port":"80"},{"ip":"61.234.249.107","port":"8118"},{"ip":"200.20.168.140","port":"80"} ,{"ip":"111.1.46.176","port":"55336"},{"ip":"120.203.158.149","port":"8118"},{"ip":"70.39.189.6","port":"9090"} ,{"ip":"210.6.237.191","port":"3128"},{"ip":"122.155.195.26","port":"8080"}]; module.exports.GetProxy = function () { var randomNum = parseInt(Math.floor(Math.random() * PROXY_LIST.length)); var proxy = PROXY_LIST[randomNum]; return 'http://' + proxy.ip + ':' + proxy.port;}proxylist.js对app.js代码做如下修改
/** 功能: 数据采集* 创建人: Wilson* 时间: 2015-07-29*/var request = require('request'), cheerio = require('cheerio'), URL_36KR = 'http://36kr.com/', //36氪 Proxy = require('./proxylist.js'); .../* 数据请求 */function dataRequest(dataUrl){ request({ url: dataUrl, proxy: Proxy.GetProxy(), method: 'GET' }, function(err, res, body) { ... }}...dataCollectorStartup()setInterval(dataCollectorStartup, 10000); 这样就改造完成，加入代码，并且加了setInterval进行定间隔执行！
上面示例中采集http请求，如果换成https呢？
新建app2.js，代码如下
/** 功能: 请求HTTPS* 创建人: Wilson* 时间: 2015-07-29*/var request = require('request'), URL_INTERFACELIFE = 'https://interfacelift.com/wallpaper/downloads/date/wide_16:10/';/* 开启数据采集器 */ functi
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